textproduct: Rapid City

KEY MESSAGES

- A hot, dry, and breezy weather pattern is expected from Monday through much of this week resulting in near-critical to critical fire weather conditions; next chance of showers and thunderstorms holds off until at least Thursday, if not Friday.

- A FIRE WEATHER WATCH has been issued for western South Dakota for Monday; a dry cold front crossing the region will also result in a sudden gusty shift from south to northwest winds.

- Slightly cooler temperatures and slightly higher relative humidities behind the front may result in a modest lull in fire weather conditions Tuesday, before conditions worsen again for Wednesday and Thursday.

UPDATE

UPDATE 2 - Issued at 541 AM MDT Sun May 10 2026

The FROST ADVISORY will be allowed to expire at 7 AM this morning as scheduled. A few localized spots have seen temperatures as cold as 35 degrees, especially in northeastern Wyoming, but most areas are currently sitting at 37 to 41 degrees (or a bit warmer up toward the Buffalo region) and should start to warm quickly after 7-8 AM. Also, in coordination with surrounding NWS offices, we issued a FIRE WEATHER WATCH for Monday across almost all of western South Dakota...the first day of our hot, dry, breezy pattern for the week. Of special note will be a sudden wind shift along the dry cold front Monday as well (still thinking mid- level moisture will be too lacking with the front for anything beyond cumulus buildups Monday afternoon/evening for now). Please refer to our Fire Weather Watch (RFW) and Fire Weather Forecast (FWF) products for additional details.

UPDATE 1 - Issued at 1109 PM MDT Sat May 9 2026

No significant changes were made to the forecast with this evening's update...but some thoughts: FROST ADVISORY remains in effect from 2 AM to 7 AM tonight/Sunday morning for portions of northeastern Wyoming and northwestern South Dakota. It's a messy and marginal setup as current temperatures are starting off in the 40s and 50s, NBM forecast lows barely dip into the 33-37 degree range (and that's the coldest guidance among our models and blends), and we're monitoring varying areas of clouds on satellite tracking southeast across the region which may provide some insulation at times, but a trend toward some greater clearing is possible toward sunrise and we certainly don't have confidence to back off on the risk at this time. Looking ahead to Monday, FIRE WEATHER WATCHES or RED FLAG WARNINGS may eventually be needed as we kick off a very hot, dry, and breezy upcoming week...with minimum RH values dropping to 10-20 percent, high temperatures reaching 85-95 degrees, and winds generally gusting over 25 MPH just about everywhere for our first day Monday. Still reviewing guidance and discussing with neighboring offices on potential alerts, which may or may not be issued this shift. Greenup in our fuels has been most prevalent north of I-90 and more limited south which will be a factor to consider, but generally speaking...massive climatological precip deficits and ongoing drought across region will likely continue to support an environment that will carry fire in many areas. Also, amidst longwave ridging, a cold front is forecast to drop southeast across the region Monday afternoon and Monday evening introducing a sharp and gusty wind shift from south to northwest into fire weather considerations...and the briefly "fresher" airmass behind this front is why we continue to think Tuesday may offer a modest lull in next week's fire weather concerns as high temperatures back off into the 70s and min RH values nudge up to 16-25 percent just for one day. This front does appear to be dry on most guidance, but could conceivably envision a scenario (hinted at perhaps in the 00z NAMNest?) where a thunderstorm or two could fire along or just behind the boundary Monday afternoon/evening. Some shear and instability will be in place along with steep lapse rates, but will we have enough mid-level moisture to support anything beyond cumulus buildups? Will not be making any changes to our dry PoPs for now, but something we will continue to evaluate in future forecast updates. AND, any isolated storm would pose the added risk of lightning into the fire weather mix. Stay tuned.

DISCUSSION

(This Evening Through Next Saturday) Issued at 1251 PM MDT Sat May 9 2026

The forecast for western SD and NE WY could be broken up into 3 parts: the continuing showers and isolated thunderstorms late this afternoon through this evening, below-normal overnight temps tonight into tomorrow morning, and the very warm weather next week.

Currently, showers and thunderstorms are tracking southeast through NE WY and SW SD. These showers will continue on this track through the rest of today and are expected to fade out later this evening. While no severe weather is expected, the stronger cells could produce gusty winds and small hail.

Saturday night into Sunday morning could be on the chilly side for folks in NE WY, the Black Hills, and far northwestern SD. Overnight lows look to dip into the low to mid 30s. The rest of the SD plains look to dip into the upper 30s to lower 40s.

Looking to next week, upper ridge slides over the Rockies and into the northern and central plains. This will give much warmer temperatures and dry conditions Monday through the rest of the next week. Main forecast concern in this time frame will be increased fire weather conditions given the hot temperatures, dry air, and breezy winds.

AVIATION

(For the 18Z TAFS Through 18Z Monday) Issued At 1124 AM MDT Sun May 10 2026

VFR conditions are expected through the TAF period.